Method and apparatus for processing and receiving digital broadcast signal for 3-dimensional subtitle

ABSTRACT

The disclosed method for processing a digital broadcast signal including a 3-dimensional, 3D, content comprises encoding 3D video data for the 3D content, the 3D video data including a left picture for a left view and a right picture for a right view for a 3D image, generating signaling data including a subtitle segment having information for signaling 3D subtitles for the 3D content, and transmitting the digital broadcast signal including the encoded 3D video data and generated signaling data.

Pursuant to 35 U.S.C. §119(e), This application claims the benefit ofU.S. Provisional Application No. 61/349,884 filed on May 30, 2010, U.S.Provisional Application No. 61/374,251 filed on Aug. 16, 2010 and U.S.Provisional Application No. 61/413,900 filed on Nov. 15, 2010 which arehereby incorporated by reference as if fully set forth herein.

TECHNICAL FIELD

The present invention relates to a method for transmitting athree-dimensional (3D) image over a network and a broadcast receiver forprocessing a broadcast signal including a 3D image and, moreparticularly, to a broadcast signal processing method for providing a 3Deffect to a subtitle displayed along with a 3D image and a broadcastreceiver for receiving a broadcast signal processed using the broadcastsignal processing method.

BACKGROUND ART

Generally, a three dimensional (3D) image (or a stereoscopic image)provides a user's eyes with a stereoscopic effect using the stereoscopicvisual principle. A human being feels both near and far through abinocular parallax caused by a distance between their eyes spaced apartfrom each other by about 65 mm, such that the 3D image enables bothright and left eyes to respectively view associated planar images,resulting in the stereoscopic effect and the perspective effect.

The above-mentioned 3D image display method may be classified into astereoscopic scheme, a volumetric scheme, a holographic scheme, etc. Incase of using the stereoscopic scheme, the 3D image display methodprovides a left view image to be viewed by the left eye and a right viewimage to be viewed by the right eye, such that the user's left eye viewsthe left view image and the user's right eye views the right view imagethrough either polarization glasses or a display device, resulting inrecognition of the 3D image effect.

DISCLOSURE Technical Problem

An object of the present invention devised to solve the problem lies inefficient transmission of a 3D subtitle displayed along with 3D contentof a broadcast signal.

An object of the present invention devised to solve the problem lies inprovision of an efficient and convenient broadcast environment to a userby processing and displaying received 3D subtitle data in considerationof a display condition of a 3D video display device and a 3D effect ofcontent set during manufacture in the case where a broadcast receiverreceives subtitle data in a 3D broadcast environment.

Technical Solution

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, amethod for processing a digital broadcast signal including a3-dimensional, 3D, content is suggested. The method comprises encoding3D video data for the 3D content, the 3D video data including a leftpicture for a left view and a right picture for a right view for a 3Dimage, generating signaling data including a subtitle segment havinginformation for signaling 3D subtitles for the 3D content, wherein thesubtitle segment includes sub-region disparity information indicatingvalue of disparity applied to at least one sub-region of a region of the3D image for the 3D subtitles, the disparity being a difference betweenhorizontal positions of a pixel representing a same point in space inthe right and left view of the 3D image, and transmitting the digitalbroadcast signal including the encoded 3D video data and generatedsignaling data.

In another aspect of the present invention, provided herein is anapparatus for receiving a digital broadcast signal including a3-dimensional, 3D, content comprising a receiving unit configured toreceive the digital broadcast signal including 3D video data for the 3Dcontent and signaling data, a demultiplexer configured to demultiplexthe 3D video data and the signaling data from the received digitalbroadcast signal, the 3D video data including a left picture for a leftview and a right picture for a right view for a 3D image, an extractingunit configured to extract a subtitle segment having information forsignaling 3D subtitles for the 3D content from the demultiplexedsignaling data, wherein the subtitle segment includes sub-regiondisparity information indicating value of disparity applied to at leastone sub-region of a region of the 3D image for the 3D subtitles, thedisparity being a difference between horizontal positions of a pixelrepresenting a same point in space in the right and left view of the 3Dimage, and a control unit configured to control a display of the 3Dsubtitle for the 3D content based on the extracted subtitle segment.

In another aspect of the present invention, the value of disparity isapplied symmetrically to each view of the region or sub-region.

In another aspect of the present invention, the subtitling segmentfurther includes information indicating existence of sub-regions in theregion of the 3D image, and wherein the value of disparity indicated bythe sub-region disparity information is applied to the region when theinformation indicates no sub-regions exist in the region.

In another aspect of the present invention, the subtitling segmentfurther includes default disparity information specifying defaultdisparity value which is applied to all regions in the 3D image when adigital broadcast receiver is not capable of applying individualdisparity values to each region.

In another aspect of the present invention, the sub-region disparityinformation includes integer part information specifying integer part ofthe value of disparity and fractional part information specifyingfractional part of the value of disparity.

In another aspect of the present invention, the subtitling segmentfurther includes sub-region horizontal information specifying horizontalposition of the at least one sub-region and sub-region width informationspecifying horizontal width of the at least one sub-region.

In another aspect of the present invention, the subtitling segmentfurther includes shift type information specifying that the value ofdisparity is applied to which view among the left and right view for the3D subtitle.

Advantageous Effects

According to the present invention, it is possible to efficientlytransmit a 3D subtitle along with 3D content through a broadcast signal.

In addition, according to the present invention, it is possible toefficiently process a 3D subtitle in a broadcast receiver.

Furthermore, according to the present invention, it is possible toprocess a 3D subtitle according to performance of a broadcast receiver.

In addition, according to embodiments of the present invention, a 3Dsubtitle data processing method maintains compatibility with a 2D legacybroadcast receiver, and at the same time displays subtitle data having a3D effect through a broadcast receiver capable of displaying 3D videodata.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

FIG. 1 is a diagram showing the syntax of an extended display definitionsegment according to an embodiment of the present invention.

FIG. 2 is a diagram showing the syntax of an extended page compositionsegment according to an embodiment of the present invention.

FIG. 3 is a diagram showing a display position of a subtitle accordingto the display_shift_type field according to an embodiment of thepresent invention.

FIG. 4 is a diagram showing a display position of a subtitle of theregion_shift_type according to an embodiment of the present invention.

FIG. 5 is a diagram showing the syntax of an extended object disparitysegment according to an embodiment of the present invention.

FIG. 6 shows a syntax structure of an extended Display DefinitionSegment (DDS) acting as extended subtitle display information accordingto one embodiment of the present invention.

FIG. 7 shows a syntax structure of an extended Page Composition Segment(PCS) acting as extended subtitle display information according to oneembodiment of the present invention.

FIG. 8 is a diagram showing the syntax of an extended object definitionsegment according to another embodiment of the present invention.

FIG. 9 is a block diagram illustrating a decoding block in a broadcastreceiver for receiving and processing 3D subtitle data according to oneembodiment of the present invention.

FIG. 10 is a block diagram showing a receiver for receiving a digitalbroadcast signal according to an embodiment of the present invention.

FIG. 11 is a flowchart illustrating a method of processing a 3D subtitleto be transmitted according to an embodiment of the present invention.

BEST MODE

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.

Prior to describing the present invention, it should be noted that mostterms disclosed in the present invention are defined in consideration offunctions of the present invention and correspond to general terms wellknown in the art, and can be differently determined according tointention of those skilled in the art, usual practices, or introductionof new technologies. In some cases, a few terms have been selected bythe applicant as necessary and will hereinafter be disclosed in thefollowing description of the present invention. Therefore, it ispreferable that the teems defined by the applicant be understood on thebasis of their meanings in the present invention.

The 3D image display method includes a stereoscopic imaging scheme inwhich two view points are considered and a multi-view imaging scheme inwhich three or more view points are considered. In contrast, a singleview image scheme shown in the related art may also be referred to as amonoscopic image scheme.

The stereoscopic imaging scheme is designed to use one pair of right andleft view images acquired when a left-side camera and a right-sidecamera spaced apart from each other by a predetermined distance capturethe same target object. The multi-view imaging scheme uses three or moreimages captured by three or more cameras spaced apart by a predetermineddistance or angle. Although the following description disclosesembodiments of the present invention using the stereoscopic imagingscheme as an example, the inventive concept of the present invention mayalso be applied to the multi-view imaging scheme.

A stereoscopic image or multi-view image may be compressed and codedaccording to a variety of methods including a Moving Picture ExpertsGroup (MPEG) scheme, and transmitted to a destination.

For example, a stereoscopic image or a multi-view image may becompressed and coded according to the H.264/Advanced Video Coding (AVC)scheme, and transmitted. In this case, the reception system may decode areceived image in reverse order of the H.264/AVC coding scheme, suchthat it is able to obtain the 3D image.

In addition, one of a left view image and a right view image of astereoscopic image or one of multiple-view images may be assigned to animage of a base layer, and the remaining one may be assigned to an imageof an extended layer. The base layer image may be encoded using the samemethod as the monoscopic imaging method. In association with theextended layer image, only information of the relationship between thebase layer image and the extended layer image may be encoded andtransmitted. As an exemplary compression coding scheme for the baselayer image, a JPEG, an MPEG-2, an MPEG-4, or a H.264/AVC scheme may beused. For convenience of description, the H.264/AVC scheme may beexemplarily used in one embodiment of the present invention. In oneembodiment of the present invention, the compression coding scheme foran image of an upper or higher layer may be set to the H.264/Multi-viewVideo Coding (MVC) scheme.

When the MVC scheme is additionally applied to the AVC scheme or theright/left image sequences are coded using only the AVC scheme so as toimplement the stereoscopic display, one point to be duly considered whenbroadcasting corresponding 3D content data is compatibility with the 2Dbroadcast receiver of the related art. For the related broadcastreceiver incapable of supporting the 3D image display, if one of rightand left view images is encoded and transmitted according to a backwardcompatible method, the 2D broadcast receiver recognizes and outputs onlythe corresponding signal, such that it may be possible for a user toview the corresponding content data through the related device. In thefollowing description, a base layer image of a time point where contentdata is transferred for a legacy broadcast receiver may be referred toas base view video data (or a base video), and an extended layer imagetransferred for displaying a 3D image may be referred to as extendedview video data (or an extended video).

In the case of transferring the base view video data and the extendedview video data as described above, a legacy 2D broadcast receiverreceives the base video data so that it can display a 2D image, and a 3Dbroadcast receiver receives base view video data and extended view videodata so that it can display a 3D image.

In the case of displaying 3D content, a plurality of subtitles may bedisplayed on a screen according to the characteristics of the 3D contentor the use of a subtitle. In this case, the plurality of subtitles mayhave the same depth on a broadcast screen or may have different depthsin order to efficiently provide a 3D effect.

For example, in the case where a plurality of actors appears and aplurality of actors simultaneously speaks their parts in 3D content, theparts are displayed as a 3D subtitle so as to provide an effectdifferent from that of a 2D environment. That is, the depths of thesubtitles representing the parts of the actors may be differently setaccording to the depths of the actors on one screen.

As another example, while a subtitle such as a broadcast station's logodisplayed on an upper right side of a broadcast screen may be displayedat a depth closer to viewers than the depth of 3D content representing a3D effect, the subtitle associated with the 3D content may be displayedat a depth relatively far apart from the viewers.

The term ‘Subtitle’ in the following description may include not only asubtitle but also displayed image, text data, graphic image, logo, etcwhich are additionally displayed to basic video data.

The broadcast system transmits subtitle data as a variety of informationof a subtitle. At this time, the subtitle data may include not onlysubtitle display information including configuration, size, position,etc. needed for displaying a subtitle, but also information of a displaycolor of a subtitle. The subtitle display information includes displaydefinition information associated with a display window structure neededfor displaying a subtitle, page composition information, regioncomposition information, object data information, and the like. From theviewpoint of a syntax structure for data transmission, displaydefinition information may be referred to as a display definitionsegment, page composition information may be referred to as a pagecomposition segment, region composition information may be referred toas a region composition segment, and object data information may bereferred to as an object data segment.

A related broadcast signal provides only basic subtitle displayinformation. Accordingly, when a 3D broadcast receiver desires todisplay the basic subtitle display information, the basic subtitledisplay information may be represented by a 2D broadcast signal or maynot be displayed. Therefore, it is necessary to transmit informationcapable of allowing even the subtitle display information to bedisplayed in a 3D format, and a broadcast receiver capable of displayingsubtitle data in a 3D format using the above-mentioned information and adata processing method thereof are needed.

In the case of displaying a stereoscopic image, left view video data andright view video data are horizontally shifted by a predetermineddistance so as to implement a 3D effect, and then displayed. At thistime, a variety of representation values (such as a shifted distance)capable of indicating the 3D effect may be used. In accordance with theembodiment of the present invention, a disparity value will hereinafterbe used as such a representation value of the 3D effect.

The 3D effect may be acquired from the process in visual perceptionleading to the sensation of depth from two slightly differentprojections of the world onto the retinas of the eyes. The difference inthe two retinal images may be called horizontal disparity, retinaldisparity, or binocular disparity. Hereinafter, for convenience ofdescription and better understanding of the present invention, thedifference between the two retinal images will only be referred to as‘disparity’.

For example, in the case of transmitting 3D video data, respectivescenes of the 3D video data may have different 3D effects. In this case,disparity values for corresponding scenes are transmitted to a broadcastreceiver, so that the broadcast receiver controls and displays the 3Deffect using the disparity values. Although other representation values(for example, a depth value, a pixel interval, a screen size, etc.)instead of the above disparity values may be used to display the 3Deffect, it should be noted that the embodiments of the present inventionwill exemplarily use the disparity value for convenience of descriptionand better understanding of the present invention.

In the case of transmitting subtitle data using the related broadcasttransmission scheme, the 3D broadcast receiver receives base view videodata and extended view video data and displays the received base viewvideo data and the received extended view video data as 3D video data.However, the subtitle data has no information for a 3D display, suchthat it has a disadvantage in that it must display 3D video data as a 2Dformat. In this case, the subtitle can be displayed only as base viewvideo data or an extended view video data, and a user views the subtitlein a 2D format in a different way from a 3D image, so that the user mayexperience dizziness and feel fatigue of eyes.

Accordingly, it is necessary to transmit both 3D video data andinformation of a 3D effect to the related subtitle data. In this way,the 3D effect information may be inserted into the related subtitledisplay information or it is possible to transmit additional subtitledisplay information.

As a method for transmitting a 3D subtitle through a broadcast system, amethod for respectively transmitting a subtitle for a left view and asubtitle for a right view may be used, similarly to a method fortransmitting a 3D image. As another method, a method for transmittingone subtitle and a disparity value for a 3D effect together may be used.Since the depth of the subtitle is not frequently changed on a broadcastcontent screen unlike an image and a change in depth within one subtitleis unusual, the method for transmitting the subtitle using the disparityvalue is advantageous in view of transmission efficiency.

In order to transmit information associated with disparity over anetwork, a method for transmitting information associated with extendeddisparity of a subtitle segment for providing display informationassociated with the existing subtitle may be used. Such a methoddisables a legacy receiver to receive/process the extended subtitlesegment and enables the existing subtitle segment using the conventionalmethod, thereby maintaining compatibility with the conventionalbroadcast system even in the case of providing a 3D subtitle.

The extended subtitle segment may be provided in the extension form of adisplay definition segment, a page composition segment, a regioncomposition segment or an object data segment. This extension form maybe referred to as an extended display definition segment, an extendedpage composition segment, an extended region composition segment or anextended object data segment. As another example, a segment forproviding information associated with disparity may be defined to beincluded in the subtitle segment. That is, information added inassociation with disparity may be combined into one segment so as to bedefined in the extended display definition segment, the extended pagecomposition segment, the extended region composition segment or theextended object data segment.

Such a subtitle segment may be processed by a transmission unitsimilarly to the processing of the subtitle segment in the conventionalbroadcast system and may be transmitted to a broadcast receiver througha broadcast signal.

FIG. 1 is a diagram showing the syntax of an extended display definitionsegment according to an embodiment of the present invention.

The extended display definition segment (EDDS) according to theembodiment of the present invention includes information defininggraphic plane associated information added for rendering a subtitle in a3DTV. The EDDS may provide information to prevent a phenomenon whereinan object of a 3D video and a graphic plane overlap thus hindering astereoscopic effect when a subtitling service for a stereoscopic videobroadcast is provided.

The EDDS may include display definition information corresponding to anextended view. At this time, in one embodiment of the present invention,a page_id value is set to be equal to a page_id value of a DDScorresponding to a base view. A segment_type field may have a value foridentifying the EDDS.

Fields included in the EDDS will now be described.

Sync_byte is an 8-bit field that shall be coded with the value ‘00001111’. Inside a PES packet, decoders can use the sync_byte to verifysynchronization when parsing segments based on the segment_length, so asto determine transport packet loss.

The segment_type field indicates the type of data contained in thesegment data field. For example, the segment_type field identifieswhether a segment including this field is a display definition segment,a page composition segment, a region composition segment, an object datasegment, an extended display definition segment, an extended pagecomposition segment, an extended region composition segment, an extendedobject data segment or a separately defined disparity associatedsegment.

The page_id identifies the subtitle service of the data contained inthis subtitling_segment. Segments with a page_id value signaled in thesubtitling descriptor as the composition page_id, carry subtitling dataspecific for one subtitle service. Accordingly, segments with thepage_id signaled in the subtitling descriptor as the ancillary page id,carry data that may be shared by multiple subtitle services.

The segment_length shall specify the number of bytes contained in theimmediately following payload of segment

The edds_version_number field indicates the version of the extended DDS.

The display_width field indicates the maximum horizontal width in pixelsof a display assumed by a subtitling stream associated with the extendedDDS.

The display_height field indicates the maximum vertical height in linesof the display in lines of a display assumed by the subtitling streamassociated with the extended DDS.

The display_shift_type field specifies a method for outputting agraphic/subtitle for a left view and a graphic/subtitle for a rightview. More particularly, this field provides information indicatingbased on which of the left view and the right view a disparity value ofa subtitle is applied. In this case, disparity may be applied to any oneof the left view and the right view or disparity information may besymmetrically applied to the left view and the right view.

Although the meaning of the value of the display_shift_type fieldaccording to one embodiment of the present invention is defined in thefollowing description, the definition of each value is not limited andthe meaning of each value may be changed.

If the value of the display_shift_type field is set to “00”, theposition of the graphic/subtitle for the left view in a process ofblending the left and right view graphic planes for a 3D subtitle outputis not changed. That is, information associated with a subtitletransmitted through a display definition segment (DDS), a pagecomposition segment (PCS), etc. is used as information associated with asubtitle of the left view. At this time, the right view may be shiftedfrom the position of the graphic/subtitle for the base view (e.g., leftview) by a value designated in the reference_disparity so as to beoutput.

If the value of the display_shift_type field is set to “01”, the rightview graphic plane uses a conventional 2D coordinate or an originallyintended coordinate and a subtitle to be output on the left view graphicplane is shifted to the right by the reference_disparity. In this case,the right view may become a base view and the left view may become anextended view such that the reference_disparity value is applied to theleft view.

If the value of the display_shift_type field is set to “10”, a subtitleto be output on the left view graphic plane is shifted to the right by(reference_disparity/2) and a subtitle to be output on the right viewgraphic plane is shifted to the left by (reference_disparity/2) so as tobe output.

More specifically, to ensure that subtitles are placed at the correctdepth and horizontal location the disparity shift values signalled shallbe applied symmetrically to each view and by implication any objectbounded in the each view. A positive disparity shift value x shallresult in a shift of x pixels to the left in the left subtitle image anda shift of x pixels to the right in the right subtitle image. A negativedisparity shift value x shall result in a shift of x pixels to the rightin the left subtitle image and a shift of x pixels to the left in theright subtitle image.

The reference_disparity field indicates an absolute value of disparitybetween subtitles included in the left and right images. That is, sincethe disparity value may have a positive value or a negative value, onlythe absolute value of the disparity is signaled in this field.

The broadcast receiver may infer a range which does not overlap astereoscopic image signal of a 3DTV when outputting an OSD, graphic orsubtitle at certain coordinates using this value. That is, the OSD,graphic or subtitle is preferably positioned at a position closer to auser than the stereoscopic image signal of the 3DTV.

In one embodiment of the present invention, if all stereoscopic imagesignals of the 3DTV are formed behind the screen (display) (positivedisparity only), the reference_disparity may be set to 0.

FIG. 2 is a diagram showing the syntax of an extended page compositionsegment according to an embodiment of the present invention.

Referring to FIG. 2, the page composition segment (PCS) includesinformation of constituent components of a displayed subtitle. The PCSmay include usage- and positioning-information of at least one regionconstructing the displayed page. In accordance with one embodiment ofthe present invention, the extended PCS (EPCS) shown in FIG. 2 istransmitted, such that the receiver can control an output of a subtitleat an extended view.

The sync_byte field, the segment_type field, the page_id field and thesegment_length field are similar to the above-described fields of theEDDS.

The page_time_out specifies the period, expressed in seconds, afterwhich a page instance is no longer valid and consequently shall beerased from the screen, should it not have been redefined before that.The time-out period starts when the page instance is first displayed.The page_time_out value applies to each page instance until its value isredefined. The purpose of the time-out period is to avoid a pageinstance remaining on the screen “for ever” if the Integrated ReceiverDecoder (IRD) happens to have missed the redefinition or deletion of thepage instance. The time-out period does not need to be counted veryaccurately by the IRD: a reaction accuracy of −0/+5 s is accurateenough.

The page_version_number indicates version of this page compositionsegment. When any of the contents of this page composition segmentchange, this version number is incremented.

The page_state signals the status of the subtitling page instancedescribed in this page composition segment.

The processed_length is the number of bytes from the field(s) within thewhile-loop that have been processed by the decoder.

The corresponding_region_id field identifies a region to which the EPCSis applied. The corresponding_region_id field may designate the id of acorresponding region among the regions defined in the PCS.

A plurality of regions may be present on one page and a subtitledisplayed in each region may be present. At this time, thecorresponding_region_id field defines with which region a specificsubtitle is associated.

The region_shift_type field differently defines the method of outputtingthe graphic/subtitle for the left view and the graphic/subtitle for theright view in region units. That is, the region_shift_type field servesto provide information regarding the above-described display_shift_typein region units.

Hereinafter, definition according to the value of the region_shift_typefield will be described. As described above, such definition is notlimited to a specific value of the region_shift_type field.

If the value of the region_shift_type field is set to “00”, the positionof the graphic/subtitle for the left view in a process of blending theleft and right view graphic planes for a 3D subtitle output is notchanged. That is, information received in the PCS, etc. may be used forthe left view without change. At this time, the subtitle of the rightview may be shifted from the position of the graphic/subtitle for thebase view (e.g., left view) by a value designated in theregion_disparity field so as to be output.

If the value of the region_shift_type field is set to “01”, the rightview graphic plane uses a 2D coordinate or an originally intendedcoordinate and a subtitle to be output on the left view graphic plane isshifted by the value of the region_disparity field so as to be output.That is, the subtitle for the left view is shifted based on the rightview.

If the value of the region_shift_type field is set to “10”, a subtitleto be output on the left view graphic plane is shifted to the right by(region_disparity/2) and a subtitle to be output on the right viewgraphic plane is shifted to the left by (region_disparity/2) so as to beoutput. In this case, the application of the region_disparity value issimilar to the above description of the display_shift_type field.

If the value of the region_shift_type field is set to “11”, a coordinateto be output to the base view is fixed to a region_horizontal_addressregardless of the left/right and a coordinate to be output to theextended view is fixed to a region-disparity value.

The region_disparity field means a difference between the horizontalcoordinates of the base view and the extended view with respect to thecorresponding region_id (corresponding_region_id). That is, theregion-disparity field indicates an absolute value of disparity betweenthe left and right images to be applied to the corresponding region.

FIG. 3 is a diagram showing a display position of a subtitle accordingto the display_shift_type field according to an embodiment of thepresent invention.

A receiver must output graphic planes corresponding to two viewsconfiguring a stereoscopic video, that is, a base view and an extendedview, in order to output a 3D subtitle.

The receiver identifies basic information of the graphic plane to whichan OSD, graphic, subtitle, etc. is output using the DDS. The receiveralso identifies the depth information of the graphic plane using theEDDS.

Since a reference disparity value is signaled through the EDDS, alldifferent subtitle regions in a screen have the same disparity (depth).In this case, a reference disparity value may be used as a defaultdisparity value which may be used by a receiver which cannot applydifferent disparities according to regions or sub-regions.Alternatively, disparity values slightly different from the referencedisparity value may be set using an algorithm of the receiver.

The receiver according to the embodiment of the present inventionreceives a DDS and identifies size information of the graphic plane andoffset information in the entire screen. At this time, if the DDS is notpresent, the graphic plane of the SD resolution (720x576) is analyzed inone embodiment of the present invention.

The receiver receives a PCS and identifies information regarding a pageand position information of each region included in the page.

The receiver may acquire information regarding an object configuring aregion, information regarding an actual bit-map object and colorinformation necessary to render subtitle graphic data using a RegionComposition Segment (RCS), an Object Definition Segment (ODS) and aColor Look-up Table (CLUT).

The receiver identifies a reference disparity value using the EDDS, fora 3D subtitle.

Each subtitle region is output to the graphic plane corresponding to thebase view and the extended view. At this time, the disparity applied tothe subtitle is shown in FIG. 3. That is, a determination as to whetherthe base view and the extended view are respectively the left view andthe right view, a determination as to which graphic plane (left orright) the reference disparity is applied according to thedisparity_shift_type field or a determination as to at which coordinatea subtitle is positioned is made. The shift (offset) degree of thecoordinate uses the reference_disparity field of the EDDS.

The subtitles which are output to the left and right graphic planes andare displayed in regions with a 3D effect in correspondence with eachother are the same and an offset therebetween is present in the outputcoordinates of the images.

As shown in FIG. 3, if the value of the display_shift_type field is setto “00”, the subtitle of the left view may be positioned based on theregion_horizontal_address and the subtitle of the right view may bepositioned based on the value considering the reference_disparity valuein the region_horizontal_address.

If the value of the display_shift_type is set to “01”, the subtitle ofthe right view may be positioned based on the region_horizontal_addressand the subtitle of the left view may be positioned based on the valueconsidering the reference_disparity value in theregion_horizontal_address.

If the value of the display_shift_type is set to “10”, the left view andthe right view may be positioned based on the value considering ½ of thereference_disparity value in the regrion_horizontal_address.Alternatively, the reference_disparity value may be used as the shiftvalue of the left view and the right view in theregion_horizontal_address.

According to one embodiment of the present invention, even when an OSDscreen such an EPG, graphic or menu is output in a 3DTV, the referencedisparity received through the EDD may be used. At this time, as shownin FIG. 3, the coordinates of data output on the left and right graphicplanes may be controlled and, if an OSD screen exceeds the range of afull screen, adequate cropping and scaling may be necessary.

The receiver may prepare EPG, graphic, icon and menu data to be outputon the screen and determine a final offset (shift) value using thereference_disparity just before output. If the OSD screen exceeds therange of the full screen, a region protruding from the screen occurs byreference disparity. This region may be simply cropped and output.

If an important or meaningful portion is excluded during cropping,scaling must be performed before cropping. That is, if an offset valueis D when graphic data having a horizontal size of 1920 is output, aregion corresponding to D is lost in an output process. At this time, inone embodiment of the present invention, a method of applying a scalingfactor of (1920)/(1920+D) to an entire graphic screen and outputtingleft and right graphic data may be used. If scaling is performed,cropping is not necessary, but, if cropping is necessary, cropping mayalso be performed.

FIG. 4 is a diagram showing a display position of a subtitle of theregion_shift type according to an embodiment of the present invention.

The case where the value of the region_shift_type is set to “00”, “01”or “10” is similar to the case where the value of the display_shift_typeis set to “00”, “01” or “10”, a description thereof will be omitted.

If the value of the region_shift_type is “11”, the left view and theright view are not distinguished and the subtitle of the base view ispositioned based on the region_horizontal_address and the subtitle ofthe extended view is positioned using the region_disparity value. Atthis time, the region_disparity value may not be defined as the offsetvalue but may be defined as the coordinates where the subtitle of theextended view will be positioned.

As described above, if an EPCS is used to signal the disparity value ofa subtitle, since the coordinates of the extended view may be designatedfor each region, each subtitle region may have an independent disparity(depth).

A process of displaying a 3D subtitle using an EPCS will now bedescribed.

The coordinates of the subtitle region are determined through the sameprocess as a 2D subtitle and the disparity values of the left and rightgraphic planes of each region are identified using theregion_disparity_value of the EPCS.

Each subtitle region is output on the graphic plane corresponding to thebase view or the extended view. At this time, the final coordinates ofthe subtitle included in each base view or extended view are determinedusing the method shown in FIG. 4. That is, a determination as to whetherthe base view and the extended view are respectively the left view andthe right view, a determination as to on which graphic plane (left orright) a base subtitle and a subtitle with an offset are outputaccording to the disparity_shift_type, or at which coordinates thesubtitle is positioned is made. The shift (offset) degree of thecoordinates may use the region_disparity_value of the correspondingregion.

The EDDS may not be present. In this case, a reference disparity whichmay be used when an OSD screen such as EPG, graphic or menu is output isnot present. In this case, the receiver may select a maximum absolutevalue among the region_disparity values of the region which is currentlydisplayed and may randomly use the maximum absolute value as thereference disparity value.

A procedure of processing a 3D subtitle in a receiver according to anembodiment of the present invention will now be described.

The receiver receives a broadcast stream. The broadcast stream includesservice information. The receiver parses a Program Map Table (PMT) inthe service information.

The receiver parses the subtitling_descriptor within the parsed PMT anddetermines whether a 3D subtitle of specific 3D content is present usingthe subtitling_type field of the subtitling_descriptor. At this time, ifit is determined that the 3D subtitle of the specific 3D content ispresent, information indicating that the 3D subtitle of the specific 3Dcontent is present may be displayed on the screen through OSD, etc. suchthat a viewer selects the 3D subtitle.

The receiver identifies a packet for transmitting a segment includingsubtitle-associated information included in the broadcast stream. Forexample, if a PES packet having a data_identifier field value of 0x20and a subtitle_stream_id value of 0x00 is identified and the segmentassociated with signaling of the subtitle in the packet is parsed.

At this time, the receiver may determine the type of the segment usingthe value of the segment_type field.

For example, the segment is a page composition segment for the base viewif the value of the segment_type field is 0x10, is a region compositionsegment for the base view if the value of the segment_type field is0x11, is a CLUT definition segment for both the base view and theextended view if the value of the segment_type field is 0x12, is anobject data segment for the base view if the value of the segment_typefield is 0x13, is a display definition segment for the base view if thevalue of the segment_type field is 0x14, is a page composition segmentfor the extended view if the value of the segment_type field is 0x40, isa region composition segment for the extended view if the value of thesegment_type field is 0x41, is an object data segment for the extendedview if the value of the segment_type field is 0x43, and is a displaydefinition segment for the extended view if the value of thesegment_type field is 0x44.

The receiver may acquire display information of the subtitle for thebase view using the DDS and/or PCS. In addition, the receiver may decodepixel-data_sub-block data included in the object data segment (ODS) andacquire a pseudo-color value of a logo or a subtitle to be output on thebase view graphic plane. In addition, the pseudo-color may be convertedinto color information to be actually output on the display using theCLUT definition segment. That is, the color information of the subtitleto be output on the base view graphic plane may be acquired.

Next, the receiver identifies display information such as the size, theposition, the object configuration information of the subtitle for theextended view using the EDDS and/or EPCS. At this time, the coordinatesof the subtitle positioned in the base view and the extended view may becorrected by the display_shift_type or the region_shift_type. In thisprocess, in the embodiment of the present invention, when thecoordinates of the subtitle are determined at each region level,information regarding the EPCS may be set to be prior to informationregarding the EDDS. That is, when a conflict occurs in thedisparity_shift_type or disparity value, the information regarding theEPCS may override the information regarding the EDDS.

FIG. 5 is a diagram showing the syntax of an extended object disparitysegment according to an embodiment of the present invention.

According to one embodiment of the present invention, disparityinformation may be differently applied according to regions included ina 3D image or according to sub-regions or objects in a region.Additional information may be included in an extended object disparitysegment (EODS) or in a newly defined segment for providing informationassociated with disparity.

The ODS may include data of a plurality of displayed objects. In oneembodiment of the present invention, an EODS shown in FIG. 5 istransmitted, so that a receiver can control an output of a subtitle atan extended view.

The sync_byte field, the segment_type field, the page_id field and thesegment_length field are similar to the above-described EDDS.

The disparity_version_number field identifies version/update informationof the EODS.

The region_id field identifies a region in a page and the object_idfield identifies an object included in a region.

The target_view_position field may indicate based on which view a 3Dsubtitle to which disparity is applied is implemented using informationregarding the object disparity segment. For example, in the case where ahorizontal address calculated using the conventional 2D subtitle schemeis N, the base view and the extended view respectively become N andN+object disparity_value, if the value of this field is “0”. Incontrast, if the value of this field is “1”, the horizontal addresses ofthe objects of the base view and the extended view respectively haveN−object_disparity_value and N.

The object_disparity_value field means a disparity value between anobject applied to the target_view_position and an object applied toanother view position and this value indicates the horizontaldisplacement of the corresponding subtitle object between the left andright views.

The disparity determined by the target_view_position field and theobject_view_position field may be applied to the object identified bythe region_id field and the object_id field.

A process of applying disparity to each object and displaying a 3Dsubtitle in a receiver will now be described. The following process isonly exemplary and may be partially changed or omitted. Alternatively,some steps may be added to the following process.

The receiver receives a broadcast stream. The broadcast stream includesservice information. The receiver parses a Program Map Table (PMT)contained in the service information.

The receiver parses a subtitling_descriptor within the PMT anddetermines whether a 3D subtitle of specific 3D content is present usinga subtitling_type field of the subtitling_descriptor. If it isdetermined that the 3D subtitle of the specific 3D content is present,information indicating that the 3D subtitle of the specific 3D contentis present may be displayed on the screen through OSD, etc. such that aviewer selects the display of the 3D subtitle.

The receiver identifies a packet for transmitting a segment includingsubtitle-associated information included in the broadcast stream. Forexample, a PES packet having a data_identifier field value of 0x20 and asubtitle_stream_id value of 0x00 is identified and a segment associatedwith signaling of the subtitle in the packet is parsed.

At this time, the receiver may determine the type of the segment using asegment_type field value.

For example, the receiver may determine that the segment is a pagecomposition segment for the base view if the value of the segment_typefield is 0x10, that the segment is a region definition segment for thebase view if the value of the segment_type field is 0x11, that thesegment is a CLUT definition segment for the extended view if the valueof the segment_type field is 0x12, that the segment is an object datasegment for the base view if the value of the segment_type field is0x13, that the segment is a display definition segment for the base viewif the value of the segment_type field is 0x14, and that the segment isan object data segment for the extended view if the value of thesegment_type field is 0x43.

The receiver identifies a region and object to which the 3D subtitle isapplied, using a region_id field and an object_id field included in theEODS.

The receiver may acquire display information of the subtitle for thebase view using the DDS and/or PCS. The receiver may decodepixel-data_sub-block included in the object data segment (ODS) andacquire a pseudo-color value of a logo or subtitle to be output on thebase view graphic plane. In addition, the pseudo-color may be convertedinto color information to be actually output on the display using theCLUT definition segment. That is, the color information of the subtitleto be output on the base view graphic plane may be acquired.

Next, position information indicating where the already decoded objectwill be output on the extended view graphic plane is identified usingthe object_disparity_value included in the EODS. The receiver determinesthe coordinates of the 3D subtitle in each view plane using thetarget_view_position information and performs 3D formatting of twographic planes, thereby outputting a 3D graphic/subtitle/logo.

FIG. 6 shows a syntax structure of an extended Display DefinitionSegment (DDS) acting as extended subtitle display information accordingto one embodiment of the present invention.

The DDS includes display width information and display heightinformation of a TV image in which a DVB subtitle is rendered. In otherwords, the DDS indicates a display size of a video image including asubtitle stream to be displayed. In one embodiment of the presentinvention, an extended DDS (DDS_EXT) shown in FIG. 6 is transmitted, sothat a receiver can control an output of a subtitle at an extended view.

Individual fields of the extended DDS shown in FIG. 6 are as follows.

A ‘dds_version_number’ field may indicate a version of the extended DDS.

A ‘display_window_flag’ field may indicate whether a subtitle displayset associated with the extended DDS is intended to be rendered in awindow within the display size defined by ‘display_width’ and‘display_height’ fields or to be rendered directly within the displaysize defined by ‘display_width’ and ‘display_height’ fields.

A ‘display_width’ field may indicate a maximum horizontal width inpixels of a display assumed by a subtitling stream associated with theextended DDS.

A ‘display_height’ field may indicate a maximum vertical height in linesof a display in lines of a display assumed by a subtitling streamassociated with the extended DDS.

A ‘display_window_horizontal_position_minimum’ field may indicate aleft-hand most pixel of a subtitle display set with reference to aleft-hand most pixel of a display.

A ‘display_window_horizontal_position_maximum’ field may indicate aright-hand most pixel of a subtitle display set with reference to aleft-hand most pixel of a display.

A ‘display_window_vertical_position_minimum’ field may indicate an uppermost line of a subtitle display set with reference to a top line of adisplay.

A ‘display_window_vertical_position_maximum’ field may indicate a bottomline of a subtitle display set with reference to a top line of adisplay.

The above-mentioned fields may be pre-contained in the DDS, and then betransmitted. In this case, information of the same or duplicated fieldshaving been transmitted in the DDS is omitted and as such only thefollowing information may be transmitted.

A ‘page_id’ field may indicate an identifier (ID) of a page on which asubtitle is displayed. In case of a ‘page_id’ value, the subtitle willbe displayed on the same page at a base view and an extended view, sothat the ‘page_id’ value may be identical to a ‘page_id’ value of a DDScorresponding to the base view, and then be transmitted.

A ‘segment_type’ field may have a value different from a related DDSvalue (e.g., 0x14), and must have a specific value (e.g., 0x44) capableof identifying an extended DDS.

A ‘target_view_position’ field may indicate a view position to which theextended DDS is applied. In other words, the ‘target_view_position’field indicates viewpoint information for displaying a stereoscopicsubtitle. For example, if the subtitle display of a correspondingextended DDS is applied to a left image, the ‘target_view_position’field may be set to a value of ‘0’. If the subtitle display of acorresponding extended DDS is applied to a right image, the‘target_view_position’ field may be set to a value of ‘1’.

A ‘minimum_disparity_value’ field may indicate a minimum value of adisparity capable of being represented by a left image and a rightimage. The lower the disparity value of the ‘minimum_disparity_value’field (i.e., the closer the disparity value of the‘minimum_disparity_value’ field is to a negative value), the imageforming position gradually moves to the front of the screen.

A ‘maximum_disparity_value’ field may indicate a maximum value of adisparity value capable of being represented by a left image and a rightimage. The higher the disparity value of the ‘maximum_disparity_value’field (i.e., the closer the disparity value of the‘maximum_disparity_value’ field is to a positive value), the imageforming position gradually moves to the interior of the screen.

The extended DDS may define the range of a disparity value capable ofbeing allocated when a subtitle is displayed through the‘minimum_disparity_value’ field 1040 and the ‘maximum_disparity_value’field.

As described above, in association with the DDS, the extended DDSincludes not only viewpoint allocation information for individualsubtitles, but also 3D effect information (i.e., disparity values), suchthat a receiver can display a subtitle having the 3D effect.

FIG. 7 shows a syntax structure of an extended Page Composition Segment(PCS) acting as extended subtitle display information according to oneembodiment of the present invention.

Referring to FIG. 7, the PCS includes information of constituentcomponents of a displayed subtitle. The PCS may include usage- andpositioning-information of at least one region constructing thedisplayed page. In accordance with one embodiment of the presentinvention, the extended PCS (PCS_EXT) shown in FIG. 7 is transmitted,such that the receiver can control an output of a subtitle at anextended view.

Individual fields of the extended PCS shown in FIG. 7 are as follows.

A ‘page_id’ field may indicate an identifier (ID) of a page on which asubtitle is displayed. In case of a ‘page_id’ value, the subtitle willbe displayed on the same page at a base view and an extended view, sothat the ‘page_id’ value may be identical to a ‘page_id’ value of a DDScorresponding to the base view, and then be transmitted.

A ‘page_time_out’ field may indicate a period, expressed in seconds,after which a page instance is no longer valid and consequently shall beerased from the screen, should it not have been redefined before that.

A ‘page_version_number’ field may indicate a version of the extendedPCS.

A ‘page_state’ field may indicate a status of a subtitling page instancedescribed in the extended PCS.

A ‘region_id’ field may indicate a unique identification of a regionwithin a page. The ‘region_id’ field may display a subtitle in the sameregion at the base view and the extended view, such that it is identicalto a ‘region_id’ value of a PCS corresponding to the base view and thentransmitted.

A ‘region_horizontal_address’ field indicates a horizontal address of atop left pixel of this region. The left-most pixel of the active pixelshas a horizontal address of zero, and the pixel address increases fromleft to right.

A ‘region_vertical_address’ field may indicate a vertical address of atop line of this region. The top line of the frame is a line of zero,and the line address increases by one within the frame from top tobottom.

A ‘target_view_position’ field may indicate a view position at which theextended PCS is applied. That is, the ‘target_view_position’ field mayindicate viewpoint information for displaying a stereoscopic subtitle.For example, if a subtitle display of a corresponding extended PCS isapplied to a left image, the ‘target_view_position’ field may be set toa value of ‘0’. If a subtitle display of a corresponding extended PCS isapplied to a right image, the ‘target_view_position’ field may be set toa value of ‘1’.

A ‘region_disparity_value’ field may indicate a disparity between afirst region applied to the left image and a second region applied tothe right image. The ‘region_disparity_value’ field may indicate ahorizontal displacement of other view on the basis of a target view. Inthe case of transmitting a value of ‘region_disparity_value’ field, a‘region_horizontal_address’ field and a ‘region_vertical_address’ fieldmay be redundant, so that the redundant fields may be omitted asnecessary.

For example, it is assumed that the ‘target_view_positon’ field of theextended PCS has a value of 1, the ‘region_disparity_value’ field has avalue of 20, and the ‘region_horizontal_address’ field has a value of N.In this case, a subtitle for the extended PCS is displayed as a rightimage, and a subtitle for the PCS is displayed as a left image. In thiscase, the horizontal position of the subtitle displayed on the leftimage is ‘N’, the horizontal position of the subtitle displayed on theright image is ‘N−20’, so that a binocular parallax is generated inresponse to a difference in horizontal positions between the left imageand the right image, resulting in the occurrence of a 3D effect.

Configuration of subtitle display information for displaying astereoscopic subtitle in accordance with one embodiment of the presentinvention and a method for processing the subtitle display informationwill hereinafter be described.

The configuration and process of a Display Definition Segment (DDS) anda Page Composition Segment (PCS) for displaying a stereoscopic subtitleaccording to one embodiment of the present invention will hereinafter bedescribed.

In order to allow a receiver to display a stereoscopic subtitle, thereceiver must receive subtitle information of two views, i.e., onesubtitle information for a base view and the other subtitle informationfor an extended view. A transmission system can transmit a DDS and a PCSfor the base view and the extended DDS and the extended PCS for theextended view.

In this case, in the case where a value incapable of being recognized bya related 2D broadcast receiver is established in a segment type of eachof the extended DDS and the extended PCS, and is then transmitted, therelated 2D broadcast receiver discards the extended DDS and the extendedPCS, and controls a subtitle display using the DDS and the PCS. The 3Dbroadcast receiver controls a subtitle display for the base view usingthe DDS and the PCS, and controls a subtitle display for the extendedview using the extended DDS and the extended PCS, so that it can displaya subtitle having the 3D effect.

Next, the configuration and process of a Region Composition Segment(RCS) for displaying a stereoscopic display according to anotherembodiment of the present invention will hereinafter be described.

The RCS may include information about a list of displayed objects andinformation about positions of the objects in the region. In the case oftransmitting the extended PCS, a segment type value incapable of beinganalyzed by the related 2D broadcast receiver may be established in theextended RCS corresponding to a region identifier (ID) contained in theextended PCS so as to prevent operations of the related 2D broadcastreceiver from being affected, and the established segment type value isthen transmitted. In the case of transmitting the extended RCS inaccordance with one embodiment of the present invention, the segmenttype value may be set to ‘0x41’. In this case, the extended RCS may havethe same structure as in the related RCS.

In addition, region composition information for the extended view may betransmitted using the RCS (i.e., segment type=0x11) instead of using theextended RCS. In this case, the region ID of this RCS is unavailable inthe received PCS, so that the related 2D broadcast receiver can discardthe above RCS.

The configuration and process of an Object Data Segment (ODS) fordisplaying a stereoscopic subtitle according to another embodiment ofthe present invention will hereinafter be described in detail.

The RCS or the extended RCS includes object information for constructingthe region, and detailed information of a corresponding object may becontained in the ODS and then be transmitted. In this case, in order toprevent operations of the related 2D broadcast receiver from beingaffected, the extended ODS for describing a subtitle object for theextended view may be transmitted. The extended ODS has the samestructure as in the related ODS, and may be assigned another segmenttype value (e.g., 0x43) different from that of the related ODS and thenbe transmitted.

In addition, object information for the extended view may be transmittedusing the related ODS instead of using the extended ODS. In this case,the object ID of the received ODS is unavailable, so that the related 2Dbroadcast receiver can discard the above ODS.

In accordance with one embodiment of the present invention, a variety ofcombinations may be constructed according to configurations of theabove-mentioned ‘DDS_EXT’, ‘PCS_EXT’ ‘RCS_EXT’ (or ‘RCS’), and ‘ODS_EXT’(or ‘ODS’) and methods for transmitting these segments. That is, the‘DDS_EXT’, ‘PCS_EXT’, ‘RCS_EXT’, and ‘ODS_EXT’ are not constructed tohave the same 3D effect, and are constructed to have different 3Deffects. For example, different disparity values may be assigned to the‘DDS_EXT’, ‘PCS_EXT’, ‘RCS_EXT’, and ‘ODS_EXT’. As a result, a varietyof 3D subtitle combinations which have different 3D effects according topages, regions, and objects of individual subtitles can be displayed.

According to another embodiment of the present invention, the broadcastreceiver receives a DVB broadcast stream, and extracts subtitle datafrom the received broadcast stream. In more detail, the broadcastreceiver parses a Program Map Table (PMT) from the DVB broadcast stream,obtains a PID value of a stream having a stream type (stream type=0x06),and receives a Packet Elementary Stream (PES) corresponding to a DVBsubtitle. In this case, the broadcast receiver can obtain basicinformation of a subtitle from the PMT. In accordance with oneembodiment of the present invention, the broadcast receiver determineswhether current data is a 3D subtitle by referring to a ‘subtitlingtype’ field of a ‘ subtitling_descriptor’ field contained in the PMT, sothat it can inform a user of information about the availability ornon-availability of a 3D subtitle. The broadcast receiver reads a PESpacket, which has a value ‘0x20’ of a ‘data_identifier’ field and avalue ‘0x00’ of a ‘subtitle_stream_id’ value, so that it can extractsubtitle data using the read PES packet.

The broadcast receiver performs section-filtering of the extractedsubtitle data. The broadcast receiver performs filtering of detailedinformation contained in subtitle data, and outputs the filteredinformation to a corresponding buffer. In this case, the subtitle datamay be classified as follows according to values of the ‘segment type’field.

0x10—Page Composition Segment (PCS) for Base View

0x11—Region Composition Segment (RCS) for Base View

0x12—CLUT definition segment for both Base View and Extended View

0x13—Object Data Segment (ODS) for Base View

0x14—Display Definition Segment (DDS) for Base View

0x40—extended Page Composition Segment (PCS_EXT) for Extended View

0x41—extended Region Composition Segment (RCS_EXT) for Extended View

0x43—extended Object Data Segment (ODS_EXT) for Extended View

0x44—extended Display Definition Segment (DDS_EXT) for Extended View

The broadcast receiver decodes subtitle display information for a baseview from the classified DDS, PCS, RCS, and ODS. The broadcast receiverdecodes the DDS, the PCS, the RCS, and the DDS, so that it can obtainsize information of a subtitle to be displayed, position information ofthe subtitle, object configuration information, object's uniqueinformation, and the like. Information needed for the broadcast receiverto display a subtitle at a base view may also be called subtitle controlinformation.

The broadcast receiver decodes the ODS, and parses a Color Look Up Table(CLUT), so that it determines subtitle display color information at abase view. The broadcast receiver decodes ‘pixel-data_sub-block’ datacontained in the ODS, so that it can acquire a pseudo-color value of asubtitle to be displayed on a base view graphic plane. The broadcastreceiver parses the CLUT, so that it can convert the pseudo-color valueinto information of a color to be actually displayed.

The broadcast receiver decodes extended subtitle display information forthe extended view from the extended DDS, the extended PCS, the extendedRCS (or RCS), and the extended ODS (or ODS). The broadcast receiverdecodes the extended DDS, the extended PCS, the extended RCS, and theextended ODS (or ODS), so that it can recognize size information of asubtitle to be displayed, position information of the subtitle, objectconfiguration information, object's unique information, and the like.Information needed for the broadcast receiver to display a subtitle atthe extended view may also be referred to as extended subtitle controlinformation as necessary.

The broadcast receiver decodes the extended ODS (or an ODS), and parsesa CLUT, so that it determines subtitle display color information at aextended view. The broadcast receiver decodes ‘pixel-data_sub-block’data contained in the extended ODS (or an ODS), so that it can acquire apseudo-color value of a subtitle to be displayed on the extended viewgraphic plane. The broadcast receiver parses the CLUT, so that it canconvert the pseudo-color value into information of a color to beactually displayed.

In a 3D display, a color of a left view subtitle may be equal to a colorof a right view subtitle. In this case, the broadcast receiver maydetermine only once the color information of a subtitle to be displayed,and may use subtitle color information of other viewpoint by reading thedetermined color information.

The broadcast receiver controls a subtitle for the base view and asubtitle for the extended view according to individual subtitle controlinformation, and outputs the controlled subtitles. The broadcastreceiver outputs the base view subtitle along with base view video dataaccording to subtitle control information and outputs the extended viewsubtitle along with extended view video data according to extendedsubtitle control information, so that it can display a 3D subtitle.

In the above-mentioned steps, the step for processing subtitle displayinformation for a base view subtitle and the other step for processingextended subtitle display information of an extended view subtitle neednot always be carried out in the above order. If necessary, subtitledisplay information for the extended view may be first carried out, orsubtitle display information for the base view and subtitle displayinformation for the extended view may be simultaneously carried out.

FIG. 8 is a diagram showing the syntax of an extended object definitionsegment according to another embodiment of the present invention.

Since viewers may use various types of receivers but a broadcast signalis transmitted using the same format, it is impossible to respectivelytransmit various types of broadcast signals to the receivers. Therefore,options for various receivers must be included in the same broadcastsignal.

According to the embodiment of the present invention, disparity may bedifferently applied to a 3D subtitle according to a plurality of regionsbelonging to one page or according to sub-regions or objects belongingto each region.

However, some receivers may not apply disparity to the 3D subtitleaccording to regions, sub-regions or objects. There is a need for amethod of receiving information associated with a 3D subtitle andprocessing the information without error even at such receivers.

According to the present invention, a default disparity value for suchreceivers may be transmitted along with disparity information of eachsub-region. Such receivers may equally apply the default disparity valueto the entire region.

The description of each field included in the extended object definitionsegment according to another embodiment of the present invention willnow be described. The sync_byte field, the segment_type field, thepage_id field, the region_id field and the segment_length field aresimilar to the same fields included in the above-described segment and adescription thereof will be omitted.

The subregion_version_number field indicates version information.

The subregion_extent_flag field indicates whether a sub-region ispresent in a region. That is, the subregion_extent_flag field providesinformation indicating whether the region is divided into sub-regions.In one embodiment of the present invention, if the value of thesubregion_extend_flag is “1”, it is indicated that the region is notdivided into sub-regions. That is, the region includes only onesub-region.

The region_disparity_integer_part field indicates an integer part of thedisparity value of a specific region.

The region_disparity_fractional_part field indicates a fractional partof the disparity value of the specific region.

According to the embodiment of the present invention, if thesubregion_extent_flag is “1”, since the region does not include aplurality of sub-regions (that is, the region includes only onesub-region), the disparity value to be applied to the region issignaled. Accordingly, the transmitter transmits the disparity value ofthe region using the region_disparity_integer_part field and theregion_disparity_fractional_part field.

The subregion_id field identifies a sub-region. The sub-region may bedefined as a low-level region belonging to the region. A plurality ofsub-regions may be present in the region. If only one sub-region ispresent in the region, the region has the same meaning as thesub-region.

The subregion_position_flag field indicates whether position informationof the sub-region is provided.

The region_disparity_flag field indicates whether the following fields,that is, the value of the subregion_disparity_integer_part and/or thevalue of the subregion_disparity_fractional_part field, are used as thedisparity value of the entire region. For example, if theregion_disparity_flag field is set to “1”, the disparity value of thefollowing sub-region may be recognized as the default disparity value ofthe page and/or the region. In this case, the region_disparity_flagfield for other sub-regions is set to “0” and the disparity value of thesub-region is not recognized as the default disparity value.

The subregion_horizontal_position field specifies the left-hand mostpixel position of this subregion. This value shall always fall withinthe declared extent of the region of which this is a subregion.

The subregion_width field specifies the horizontal width of thissubregion expressed in pixels. The combination ofsubregion_horizontal_position and subregion_width shall always fallwithin the declared extent of the region to which this refers.

The subregion_disparity_integer_part field indicates an integer part ofthe disparity value applied to the sub-region.

The subregion_disparity_fractional_part field indicates a fractionalpart of the disparity value applied to the sub-region.

The receiver may be largely divided into two types, one is a receiver(“A type”) in which one disparity value may be applied to one regionand/or page and the other is a receiver (“B type”) in which thedisparity value may be differently applied according to the sub-regionsand/or the objects in the region.

If the subregion_extent_flag is “1”, since the region is not dividedinto sub-regions, the A-type and B-type receiver can process thesubtitle segment.

If the subregion_extent_flag is “0”, since the sub-region is present inthe region, the B-type receiver may apply the disparity value accordingto the sub-regions using the above-described fields. Since the A-typereceiver may not apply the disparity value according to a plurality ofsub-regions, the default disparity value is applied to the entireregion. For example, if the value of the region_disparity_flag is “1”,the values of the following fields, that is, the value of thesubregion_disparity_integer_part and/or the value of thesubregion_disparity_fractional_part field, are used as the defaultdisparity value of the entire region.

A procedure of processing a 3D subtitle at a receiver based on the abovedescription will now be described.

The receiver receives a broadcast stream. The broadcast stream includesservice information. The receiver parses a Program Map Table (PMT) inthe service information.

The receiver parses a subtitling_descriptor within the parsed PMT anddetermines whether a 3D subtitle of specific 3D content is present usinga subtitling_type field of the subtitling_descriptor. If it isdetermined that the 3D subtitle of the specific 3D content is present,information indicating that the 3D subtitle of the specific 3D contentis present may be displayed on the screen through OSD, etc. such that aviewer selects the display of the 3D subtitle.

The receiver identifies a packet for transmitting a segment includingsubtitle-associated information included in the broadcast stream. Forexample, a PES packet having a data_identifier field value of 0x20 and asubtitle_stream_id value of 0x00 is identified and a segment associatedwith signaling of the subtitle in the packet is parsed.

At this time, the receiver may determine the type of the segment using asegment_type field value.

For example, the receiver may determine that the segment is a pagecomposition segment for the base view if the value of the segment_typefield is 0x10, that the segment is a region definition segment for thebase view if the value of the segment_type field is 0x11, that thesegment is a CLUT definition segment for the extended view if the valueof the segment_type field is 0x12, that the segment is an object datasegment for the base view if the value of the segment_type field is0x13, that the segment is a display definition segment for the base viewif the value of the segment_type field is 0x14, and that the segment isan object data segment for the extended view if the value of thesegment_type field is 0x43.

The receiver identifies information regarding a region in which thesubtitle is displayed using the region_id field and the subregion_idfield included in the extended object data segment (EODS, ODS_EXT). Inthis case, the region in which the subtitle is displayed may bedetermined based upon position and width information of eachsubregion-id.

The receiver identifies the size, position and object configurationinformation of the subtitle for the base view using the DDS, PCS and theregion composition segment (RCS), in order to decode the subtitle of theregion.

The receiver may decode pixel-data_sub-block data included in the objectdata segment (ODS) and acquire a pseudo-color value of a logo orsubtitle to be output on the base view graphic plane. In addition, thepseudo-color may be converted into color information to be actuallyoutput on the display using the CLUT definition segment. That is, thecolor information of the subtitle to be output on the base view graphicplane may be acquired.

The receiver calculates the region corresponding to each sub-region ofthe already decoded region in the extended view graphic plane using thedisparity of each sub-region included in the ODS_EXT.

Additionally, the receiver corrects the coordinates of each view planeof the 3D subtitle data using the disparity of each sub-region andperforms 3D formatting of two graphic planes, thereby outputting a 3Dgraphic/subtitle/logo in the stereoscopic display.

If it is difficult to apply the display in sub-region units, thesub-region having the region_disparity_flag value of “1” is selectedfrom among the sub-regions and the disparity of the selected sub-regionis applied to the entire region.

FIG. 9 is a block diagram illustrating a decoding block in a broadcastreceiver for receiving and processing 3D subtitle data according to oneembodiment of the present invention.

Referring to FIG. 9, the broadcast receiver includes a demultiplexer(denoted by ‘MPEG2 TS Demux (PID filter)’) 6010, a section filter 6020,an Extended View (EV) subtitle decoder 6030, a Base View (BV) subtitledecoder 6040, a composition buffer 6050, a CLUT processor (denoted by‘CLUT’) 6060, an EV pixel buffer 6070, a BV pixel buffer 6080, and a 3Dgraphics controller 6090.

In the broadcast receiver, a receiving unit (not shown) receives aMoving Picture Expert Group 2 Transport Stream (MPEG2 TS) includingsubtitle data, and the demultiplexer 6010 performs filtering of thereceived MPEG2 TS using a PID corresponding to subtitle data so that itextracts and outputs subtitle data.

The section filter 6020 performs section-filtering of subtitle data, sothat it outputs PCS, PCS_EXT, RCS, RCS_EXT, DDS, DDS_EXT, ODS, ODS_EXT,and Color Look Up Table Definition Segment (CLUTDS) data.

In the following description, the demultiplexer 600 for extractingsubtitle data from the received broadcast signal and the section filter6020 for extracting and outputting display information and CLUTDS of asubtitle may be contained in one extraction unit as necessary.

In this case, PCS, RCS, DDS, ODS, PCS_EXT, RCS_EXT, DDS_EXT, and ODS_EXTmay be buffered in the composition buffer 6050, and the buffered resultsmay be applied to the 3D graphics controller 6090. In addition, PCS,RCS, DDS, and ODS may be applied to the BV subtitle decoder 6040, andPCS_EXT, RCS_EXT, DDS_EXT, and ODS_EXT may be applied to the EV subtitledecoder 6030.

The CLUT processor 6060 processes the CLUTDS, so that it outputs displaycolor information to the BV pixel buffer 6080 and the EV pixel buffer6070.

The BV subtitle decoder 6040 decodes PCS, RCS, DDS, and ODS, so that itdecodes subtitle data for the base view and subtitle display informationfor the base view and outputs the decoded subtitle data and the decodedsubtitle display information to the BV pixel buffer 6080. The EVsubtitle decoder 6030 decodes PCS_EXT, RCS_EXT, DDS_EXT, and ODS_EXT, sothat it decodes subtitle data for the extended view and subtitle displayinformation for the extended view and outputs the decoded subtitle dataand the decoded subtitle display information to the EV pixel buffer6070.

The 3D graphic controller 6090 receives PCS, RCS, DDS, ODS, PCS_EXT,RCS_EXT, DDS_EXT, and ODS_EXT from the composition buffer 6050, andreceives subtitle display information for the base view, ODS and colorinformation for the base view from the BV pixel buffer 6080. The 3Dgraphics controller 6090 receives subtitle display information for theextended view, ODS_EXT and color information for the extended view fromthe EV pixel buffer 6070. The 3D graphics controller 6090 reads thereceived information, so that it controls subtitles of respectiveviewpoints and outputs the controlled subtitles.

In accordance with another embodiment of the present invention, the BVsubtitle decoder 6040 decodes the ODS and the EV subtitle decoder 6030decode the ODS_EXT, so that the BV subtitle decoder 6040 and the EVsubtitle decoder 6030 acquire information of a displayed subtitleobject. The 3D graphics controller 6090 receives coordinates-, size-,and configuration-information (for example, PCS, RCS, DDS, PCS_EXT,RCS_EXT, and DDS_EXT) of a displayed subtitle object, so that it maycontrol the 3D subtitle display using the received information.

FIG. 10 is a block diagram showing a receiver for receiving a digitalbroadcast signal according to an embodiment of the present invention.

The receiver according to the embodiment of the present inventionincludes a tuner & demodulator 10010, a VSB decoder 10020, a transportstream demultiplexer (DEMUX) 10030, a video decoder 10040, a sectionfilter 10050, a subtitle decoder 10060, a graphic engine 10070, an ODSprocessor 10080 and a formatter 10090.

The tuner & demodulator 10010 tunes to a channel for transmitting abroadcast signal and demodulates a signal.

The VSB decoder 10020 decodes a signal modulated using a VSB scheme. TheVSB decoder may decode a signal modulated using a scheme other than theVSB scheme according to a broadcast system.

The transport stream DEMUX 10030 demultiplexes transport stream data.For example, the transport stream DEMUX 10030 may separate a signalingsignal and a video/audio signal.

The video decoder 10040 decodes the video data demultiplexed from thetransport stream data. In the present invention, a 3D video elementarystream is delivered to the video decoder 10040. The video decoder 10040decodes the 3D video elementary stream into 3D video data.

The section filter 10050 serves to filter signaling data for a 3Dsubtitle. That is, the section filter 10050 filters data such as DDS,EDDS (DDS_EXT), PCS, EPCS (PCS_EXT), RCS, ERCS (RCS_EXT), ODS, EODS(ODS_EXT), CLUTDS (Colour Look Up Table Definition Segment), etc.

The subtitle decoder 10060 decodes signaling information for displayinga 3D subtitle. For example, the subtitle decoder 10060 decodes disparityinformation for the 3D subtitle. The section filter 10050 and thesubtitle decoder 10060 may be collectively referred to as an extractingunit.

The graphic engine 10070 generates a graphic element associated with asubtitle using the signaling information decoded by the subtitle decoder10060. The subtitle passing through the graphic engine 10070 is outputin 3D form. In addition, the graphic engine 10070 performs a series ofcontrol functions for displaying the 3D subtitle.

The OSD processor 10080 performs a series of functions associated withthe OSD processing of the receiver. For example, the OSD processor 10080may generate left view and right view OSDs to which the disparity valueis applied, for applying a 3D effect to the OSD. In addition, the OSDprocessor 10080 performs a series of control functions for 3D OSD.

The formatter 10090 serves to format a combination of the 3D video datadecoded by the video decoder 10040 and the 3D subtitle and/or the OSDprocessed by the graphic engine 10070 and/or the OSD processor 10080.The formatted image includes a 3D video image, a 3D subtitle and/or a 3DOSD. In addition, the formatter 10090 performs a series of controlfunctions for displaying a 3D image.

FIG. 11 is a flowchart illustrating a method of processing a 3D subtitleto be transmitted according to an embodiment of the present invention.

A transmitter for transmitting a broadcast signal encodes 3D video datafor 3D content (s11010). The 3D video data includes a left view imageand a right view image for the 3D image.

The transmitter generates signaling data including a subtitle segmentfor signaling a 3D subtitle to be displayed along with 3D content(s11020). The subtitle segment includes information indicating adisparity value applied to at least one sub-region included in a region.The disparity is a difference between horizontal positions of a pixelrepresenting the same point in space in the right and left view of the3D image.

The transmitter transmits a broadcast signal including the encoded 3Dvideo data and the generated signaling data (s11030).

Although the present invention has been described in conjunction withthe limited embodiments and drawings, the present invention is notlimited thereto. Those skilled in the art will appreciate that variousmodifications, additions and substitutions are possible from thisdescription. Therefore, the scope of the present invention should not belimited to the description of the exemplary embodiments and should bedetermined by the appended claims and their equivalents.

MODE FOR INVENTION

Various embodiments have been described in the best mode for carryingout the invention.

INDUSTRIAL APPLICABILITY

As described above, the present invention is partially or wholly appliedto a digital broadcast system.

1. A method for processing a digital broadcast signal including a3-dimensional, 3D, content, the method comprising: encoding 3D videodata for the 3D content, the 3D video data including a left picture fora left view and a right picture for a right view for a 3D image;generating signaling data including a subtitle segment havinginformation for signaling 3D subtitles for the 3D content, wherein thesubtitle segment includes sub-region disparity information indicatingvalue of disparity applied to at least one sub-region of a region of the3D image for the 3D subtitles, the disparity being a difference betweenhorizontal positions of a pixel representing a same point in space inthe right and left view of the 3D image; transmitting the digitalbroadcast signal including the encoded 3D video data and generatedsignaling data.
 2. The method of claim 1, wherein the value of disparityis applied symmetrically to each view of the region or sub-region. 3.The method of claim 1, wherein the subtitling segment further includesinformation indicating existence of sub-regions in the region of the 3Dimage, and wherein the value of disparity indicated by the sub-regiondisparity information is applied to the region when the informationindicates no sub-regions exist in the region.
 4. The method of claim 1,wherein the subtitling segment further includes default disparityinformation specifying default disparity value which is applied to allregions in the 30 image when a digital broadcast receiver is not capableof applying individual disparity values to each region.
 5. The method ofclaim 1, wherein the sub-region disparity information includes integerpart information specifying integer part of the value of disparity andfractional part information specifying fractional part of the value ofdisparity.
 6. The method of claim 1, wherein the subtitling segmentfurther includes sub-region horizontal information specifying horizontalposition of the at least one sub-region and sub-region width informationspecifying horizontal width of the at least one sub-region.
 7. Themethod of claim 1, wherein the subtitling segment further includes shifttype information specifying that the value of disparity is applied towhich view among the left and right view for the 3D subtitle.
 8. Anapparatus for receiving a digital broadcast signal including a3-dimensional, 3D, content, the apparatus comprising: a receiving unitconfigured to receive the digital broadcast signal including 3D videodata for the 3D content and signaling data; a demultiplexer configuredto demultiplex the 3D video data and the signaling data from thereceived digital broadcast signal, the 3D video data including a leftpicture for a left view and a right picture for a right view for a 3Dimage; an extracting unit configured to extract a subtitle segmenthaving information for signaling 3D subtitles for the 3D content fromthe demultiplexed signaling data, wherein the subtitle segment includessub-region disparity information indicating value of disparity appliedto at least one sub-region of a region of the 3D image for the 3Dsubtitles, the disparity being a difference between horizontal positionsof a pixel representing a same point in space in the right and left viewof the 3D image a control unit configured to control a display of the 3Dsubtitle for the 3D content based on the extracted subtitle segment. 9.The apparatus of claim 8, wherein the value of disparity is appliedsymmetrically to each view of the region or sub-region.
 10. Theapparatus of claim 8, wherein the subtitling segment further includesinformation indicating existence of sub-regions in the region of the 3Dimage, and wherein the value of disparity indicated by the sub-regiondisparity information is applied to the region when the informationindicates no sub-regions exist in the region.
 11. The apparatus of claim8, wherein the subtitling segment further includes default disparityinformation specifying default disparity value which is applied to allregions in the 3D image when a digital broadcast receiver is not capableof applying individual disparity values to each region.
 12. Theapparatus of claim 8, wherein the sub-region disparity informationincludes integer part information specifying integer part of the valueof disparity and fractional part information specifying fractional partof the value of disparity.
 13. The apparatus of claim 8, wherein thesubtitling segment further includes sub-region horizontal informationspecifying horizontal position of the at least one sub-region andsub-region width information specifying horizontal width of the at leastone sub-region.
 14. The apparatus of claim 8, wherein the subtitlingsegment further includes shift type information specifying that thevalue of disparity is applied to which view among the left and rightview for the 3D subtitle.